The invention is directed to a protective barrier coating composition that protects buildings from the destructive effects of termites, or other wood destroying insects, as well as mold or mildew, and water or fire damage.
Various methods have been used to protect buildings from being infested with termites, and many more methods used to rid the buildings of termites once infested. These protective methods are all very expensive, have a limited effective life, and use hazardous chemicals to humans and animals. To be effective, a chemical or physical barrier is necessary to eliminate all possible points of entry, preventing any connection between the wood and soil. This requires elaborate equipment and a complicated process needed to be performed by a professional pest control service. Treatment areas include the entire soil area to be covered by concrete, areas adjacent to foundation walls, treatment of footings, back fill outside foundation walls, inside walled areas where there is a crawl space, and any other possible points of entry. The chemicals used are a hazard to handle, and restricted to use by professional applicators. They will only provide protection for about 5 years. This method drenches the soil with liquid termiticide, which is not environmentally friendly. Baiting is another method to control termites. Bait stations are installed underground around the perimeter of the house every 10 to 20 feet and 2 feet out from the house. This method takes considerable time to eliminate a colony of up to one year. It relies upon individual termites feeding on the bait, and returning to the colony to pass the poison on to other members, killing a portion of the exposed colony. Often termites are not attracted to the bait, and can then seek out wood in the building to feed on.
Another method used is to pretreat the wood with chemicals by using pressure to impregnate the wood. Hazardous chemicals like CCA (chromated copper arsenate) or ACZA (ammoniacol copper zinc arsenate) have been used both against termites and fungal decay. Currently zinc borate is available in some composite products, and disodium octaborate tetrahydrate is popular for pretreatment of construction wood. These berates are water-soluble, (zinc borate less so) and can be washed out of the wood from rain on the construction site to some extent. The impregnation is highly dependent upon the density or porosity of the wood or composite material with dense areas obtaining insufficient protection. Pretreatment by impregnation is also expensive adding about $3000 for a typical 2000 square feet house. Zinc borate is known as a smoke suppressant, but has little effect upon lowering the fire spread or heat of combustion. Given the small amount impregnated into the wood, even the smoke suppression is minimal.
Lessor used methods of termite control include adding borates into a mulch that is spread around a house. This is a very short-lived protection with the borates being easily degraded in the soil, and washed away by rain.
Another method disclosed in U.S. Pat. No. 6,322,803 is to spray a structure with a mixture of a quick setting liquid monomer and a pesticide, which forms a bonded polyurethane coating upon curing. The disadvantages of this method outweigh its value since it takes special expensive two component spray equipment, and uses very hazardous isocyanate chemicals. These monomers will very quickly react with any moisture on the wood surfaces forming many carbon dioxide bubbles and pinholes in the film, leaving many entry points for the termites. Urethanes are also very flammable, and give off toxic gases in a fire.
U.S. Pat. No. 6,316,016 also describes a two component urethane system to provide a foamed polyurethane barrier on various construction materials as well as soil. Again, this method uses hazardous isocyanate chemicals as well as flammable and hazardous solvents like Methyl Ethyl Ketone, and a complicated, expensive, two component meter and mix spray equipment. The pesticides used are also hazardous, such as tribulytin compounds, chlordane, phenols, chromium, copper or arsenic compounds. This product is also flammable, and would add considerably to the flame spread and heat evolution in a fire.
U.S. Pat. No. 6,370,834 describes the use of manufactured plastic films or sheets as a barrier, and incorporating a termiticide in the material such as fipionil. The thermoplastic film or sheeting is selected from the group of polyethylene, polypropylene, polyurethane and polystyrene, all of which are very flammable. These materials are claimed to be useable as moisture barriers, but for building external walls breathable materials must be used to prevent condensate from forming within the wall cavity. Gaps or openings in joints would be inevitable, allowing for points of termite passage.
Therefore there remains the need for an effective, long term, simple, safe and inexpensive means of protecting buildings from termites, and other insect damage that is water resistive, while not contributing to the flammability of the building.